I want to second Marcia's point about making more than one block before deciding what your background will be.
The reason is revealed in your teacher's sample - - each block will look different, with different colors being accented.
The burgundy looks flat because dark colors recede, the lights in your block pop forward, and I do believe that the burgundy really highlights the red in your berries.
However <g>
I like your dark green ... it makes everything look rich, including the background.
I love colors and can hardly wait to see how you work this puzzle out <g>